The proposed research contains two programs. One is an investigation of amalgamation kinetics using Ag-Sn plus X alloys (where X is an additional element). The second is an investigation of the dissolution mechanism of constituent elements from amalgam alloys (Ag-Sn plus X). In the first experiments, several Ag-Sn alloys containing copper (up to 30 wt. percent) were melted in evacuated Vycor capsules. Optical and Scanning electron microscopy of specimens electroplated with mercury is in progress (for the plating procedure, see the publication: "Amalgamation Reaction on Mercury-Plated Dental Alloy (Ag3Sn)", J. Biomed. Mater. Res., 9, 221 (1975). In addition to silver-mercury polyhedra, mercury-copper crystals were found on some specimens. X-ray energy dispersive spectra revealed the presence of a tin-copper phase on the reacted surface of the specimens. In the second investigation, Ag3Sn samples have been plated with AG110m and with Sn113. These samples were homogenized and placed in mercury. By measuring the amount of activity in the mercury, the dissolution of Ag or Sn can be monitored as a function of time. Rate constants for dissolution of Ag from Ag3Sn into mercury have been found. Experiments now in progress will determine the dissolution rate of Sn from Ag3Sn into mercury. Comparison of the rate of dissolution of Ag and Sn should clarify the dissolution mechanism of Ag3Sn.